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-   -   1990 Honda Accord Idle fluctuation (http://www.autobanter.com/showthread.php?t=211694)

[email protected] November 20th 07 06:13 PM

1990 Honda Accord Idle fluctuation
 
My 1990 Honda Accord 2.2L started to have idle fluctuations
yesterday. The RPM will fluctuate between 1700 and 1000 RPMs when the
car is stopped. The fluctuations don't seem to be noticeable when the
car is in gear. What would cause this? I searched for vacuum leaks
but couldn't find anything. I recently did a tune-up. Please help!

Elle November 20th 07 07:28 PM

1990 Honda Accord Idle fluctuation
 
A strong candidate: Top off and monitor the cooling system. It cools certain engine
control sensors. If they are not fully immersed, then the wrong signal gets sent to the
engine control computer.

You should do a proper purge of air from the system as well, though its said over time the
air will vent itself. I prefer going through the roughly half-hour, fairly easy, idle
purge procedure described in the owner's manual and Factory Service manual.

> wrote
> My 1990 Honda Accord 2.2L started to have idle fluctuations
> yesterday. The RPM will fluctuate between 1700 and 1000 RPMs when the
> car is stopped. The fluctuations don't seem to be noticeable when the
> car is in gear. What would cause this? I searched for vacuum leaks
> but couldn't find anything. I recently did a tune-up. Please help!




Paul Jr November 20th 07 10:57 PM

1990 Honda Accord Idle fluctuation
 
On Nov 20, 10:28 am, "Elle" >
wrote:
> A strong candidate: Top off and monitor the cooling system. It cools certain engine
> control sensors. If they are not fully immersed, then the wrong signal gets sent to the
> engine control computer.
>
> You should do a proper purge of air from the system as well, though its said over time the
> air will vent itself. I prefer going through the roughly half-hour, fairly easy, idle
> purge procedure described in the owner's manual and Factory Service manual.
>


The coolant system is working properly. Any other ideas?

Tegger November 21st 07 12:46 AM

1990 Honda Accord Idle fluctuation
 
wrote in news:9ae279a7-d778-48cd-8328-5e54960c13e2
@s12g2000prg.googlegroups.com:

> My 1990 Honda Accord 2.2L started to have idle fluctuations
> yesterday. The RPM will fluctuate between 1700 and 1000 RPMs when the
> car is stopped. The fluctuations don't seem to be noticeable when the
> car is in gear. What would cause this? I searched for vacuum leaks
> but couldn't find anything. I recently did a tune-up. Please help!




I'll bet the fluctuations are only when the car is warm.

If so, it's a stuck Fast Idle Thermo Valve. There is a way to test for
that.

--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

[email protected] November 22nd 07 11:45 PM

1990 Honda Accord Idle fluctuation
 
replace the PCV valve, and clean the Mass Air Flow (MAF) sensor,
remove the idle screw and clean the assembly with carb cleaner

if that doesnt fix it then check the Idle Air Control Valve and adjust
the Fast Idle Valve,

excerpt: "its the cylinder on the driver side of the intake manifold,
with the triangular cap with 3 screws. pull them out and take the cap
off, and twist the outer white ring clockwise until its as tight as
possible, and close it back up."

http://www.honda-tech.com/zerothread/1704468


On Nov 20, 12:13 pm, wrote:
> My 1990 Honda Accord 2.2L started to have idle fluctuations
> yesterday. The RPM will fluctuate between 1700 and 1000 RPMs when the
> car is stopped. The fluctuations don't seem to be noticeable when the
> car is in gear. What would cause this? I searched for vacuum leaks
> but couldn't find anything. I recently did a tune-up. Please help!



Tegger November 23rd 07 01:59 AM

1990 Honda Accord Idle fluctuation
 
wrote in news:d75aec50-7389-41a3-aed1-b6f2395e5594
@d27g2000prf.googlegroups.com:

> replace the PCV valve, and clean the Mass Air Flow (MAF) sensor,




This car doesn't have a MAF.



> remove the idle screw and clean the assembly with carb cleaner
>
> if that doesnt fix it then check the Idle Air Control Valve and adjust
> the Fast Idle Valve,




You can't "adjust" the Fast Idle Valve. It gets stuck open on account of
neglected coolant changes and results in a massive air leak when the car is
warm.



>
> excerpt: "its the cylinder on the driver side of the intake manifold,
> with the triangular cap with 3 screws. pull them out and take the cap
> off, and twist the outer white ring clockwise until its as tight as
> possible, and close it back up."




The Fast Idle Valve on this car has two screws, has no white ring and is
non-adjustable.





--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

TE Chea November 26th 07 10:06 AM

1990 Honda Accord Idle fluctuation
 
| What would cause this?

Mine had this problem, cause was throttle angle sensor
( a variable resistor ). See
http://www.autozone.com/servlet/UiBr...r ameters=001



Paul Jr November 26th 07 03:53 PM

1990 Honda Accord Idle fluctuation
 
Yes! the fluctuations are only when the car is warm. How do I test for
a stuck Fast Idle Thermo Valve?

Thank you,
Paul

>
> I'll bet the fluctuations are only when the car is warm.
>
> If so, it's a stuck Fast Idle Thermo Valve. There is a way to test for
> that.
>
> --
> Tegger
>
> The Unofficial Honda/Acura FAQwww.tegger.com/hondafaq/




motsco_[_1_] November 26th 07 06:14 PM

1990 Honda Accord Idle fluctuation
 
wrote:
> My 1990 Honda Accord 2.2L started to have idle fluctuations
> yesterday. The RPM will fluctuate between 1700 and 1000 RPMs when the
> car is stopped. The fluctuations don't seem to be noticeable when the
> car is in gear. What would cause this? I searched for vacuum leaks
> but couldn't find anything. I recently did a tune-up. Please help!


--------------------------

Before getting too far into it, how full is your coolant reservoir? You
said you did some work on it. Did you make sure the cooling system was
full to the MAX mark afterwards? I think it's mentioned in your owner's
manual.

'Curly'

Tegger November 26th 07 10:08 PM

1990 Honda Accord Idle fluctuation
 
Paul Jr > wrote in news:43771d97-174b-4f42-ba99-
:

>
>>
>> I'll bet the fluctuations are only when the car is warm.
>>
>> If so, it's a stuck Fast Idle Thermo Valve. There is a way to test for
>> that.
>>
>>

>
>
> Yes! the fluctuations are only when the car is warm. How do I test for
> a stuck Fast Idle Thermo Valve?
>




The Fast Idle Valve is a round, sort of tower-like thing to the left
(driver's) side of the intake manifold, between the "PGM-FI" logo and the
valve cover. It has two screws on top of it that hold a sheet-metal cover
in place.

With the engine fully warmed up and the idle fluctuating, remove the two
screws and the cover of the Fast Idle Valve. Feel the valve seat area with
your finger. If there *is* air flow (suction), the valve is stuck open. You
will probably find that once you cover the valve seat with your finger the
idle will settle down.


--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/


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